1. Technical Field
This disclosure is directed to integrated circuits, and more particularly, to power management in integrated circuits in which interrupts may be invoked.
2. Description of the Related Art
In various types of computer systems (e.g., desktop computer systems, tablet computers, smart phones, etc.), circuitry may be included to handle interrupts. Such interrupts are typically invoked by various devices that are peripheral to the interrupt handler. For example, a radio unit in a smart phone may invoke an interrupt responsive to an incoming phone call. Responsive to the interrupt, the interrupt handler may invoke an interrupt handler routine. The interrupt handler routine may cause a processor or other device to perform various functions to deal with the interrupt. It is noted that in many (but not all) cases, the interrupt handler circuitry is part of a processor.
Power management is an important function in various types of computer systems, particularly those that are portable and/or rely on battery power. In such systems, portions that are idle may be placed into a low power state. Low power states may include clock-gating idle functional units and power-gating idle functional units. In some cases, individual functional units within an IC may be placed in a low power state. Peripheral functional units may also be placed in a low power state. Nevertheless, interrupts may occur in systems in which portions thereof are idle. Accordingly, interrupt handling circuitry may be left in a full power state (i.e. receiving both clock and supply voltage) despite other portions of the system being idle.